Engine speed governor



4 Sheets-Sheet 1 ENGINESPEED GOVERNOR Filed Sept. 27, 1940 \A. W. KRETZSCHMAR sept. 15, 41942.

msentor Sept. 15, X942. A. w. KRETzscHMAR ENGINE SPEED GOVERNOR Filed Sept. 27. 1940 nventor Y V J/ @777/ Gttorneg sept' 15 1942- A. w. KRE'TzscHMAR 2,296,213

ENGINESPEED GOVERNOR Filed Sept. 27, 1940 4 Sheets-Sheet 3 Sept 15, 1942- A. w. KRETzscHMAR ENGINE SPEEDl GOVERNOR Filed Sept. 27, 1940 `4 Sheets-Sheet 4 y -w @I Snventor W w, QJ/7 JW J4/ 4 /v/ j f a Peieeied sees is, 1942 UNITED STATES PATENT OFFICE Application September No. 8,678

10 Claims.

This invention relates generally to speed governors and more particularly to governors for controlling operation of carburetors of internal combustion engines.

It is an object of the present invention to provide a new and improved speed governor which is a unit separate from or external of the carburetor controlled thereby.`

Another object of the invention is to provide a speed governor having a new and improved arrangement of the operating parts thereof for improved eiliciency of operation.

A further object of the invention is to provide in a speed governor having a spring, opposing operation of the carburetor valve by engine-created suction, new and improved means carried by the spring for varying the force exerted'thereby in accordance with variations in the force of engine-created suction.

Other objects of the invention will become apparent from the following detailed description taken in connection with the accompanying drawl ings, in which:

Figure l is a view shown in longitudinal cen- 'tral section of my improved speed governor;

kalong the line 5 5 of Figure 2 to show certain details or the manual control means for the carburetor throttle valve; and

Figure 6 is a view similar to Figure 1 showing the operating parts of the speed governor in positions they will assume during idling operation of an engine.

Referring to the drawings by characters of reference, the numeral il designates in general` the intake conduit of a carburetor, the conduit having at one end thereof the usual out-turned flange Il to receive screws or" other suitable" means for rigidly securing the carburetorlto the intake manifold of an internal combustion engine, not shown. Flow of fuel and air through the carburetor conduit I0 is controlled by a throttle or so-called butterfly valve I2 in the conduit III. which valve is secured to and intermediate the ends of a shafty Il extending transversely through the side wall of the conduit l0. One end of the valve shaft Il extends externally of the carburetor conduit lil and projects into a casing l! which may be integral with and joined to the carburetor'conduit i0 by a hollow connecting conduit il or may be separate therefrom, as desired. 'I'he shaft i2 is preferably joumaled in a roller bearing i6 mounted in the conduit I4 adjacent the casing IB. The casing Il houses the operating and associated mechanismv of the speed governor and comprises a top wall Il, bottom wall Il, end walls Il and .20, a rear wall 2i and a front wall or removable cover 22. e

The end 'of the shaft i3 which projects into the casing I5 is provided with a rotatable mem- -ber or lever which is integral with the shaft to rotate therewith and is in the form of a segment of a drum 23 having its center of rotation coincident with the axis of rotation of the valve shaft il. Secured tothe periphery of the drum segment 23 is one end of a strap 24 which may be secured to the drum segment by a screw 2B, the other end of the strap being attached to a movable wall 2t of a pressure responsive bellows member-2l which is disposed within the casing Il. The other end of the bellows 21 issealed and secured around its periphery by an outtumed iiange 21a of a ntting 28 which is rigidly secured to the casing end wall i9 by screws 28. The iltting 28 may be connected by a suitable conduit, not shown, to the intake manifold of the engine whose speed is to be controlled, with the result that the bellows 21 will expand and collapse in accordance with engine-created suction and will act upon decrease in pressure in the intake manifold to move the throttle valve i2 toward closed position or counter-clockwise,

facing Figure 1.

`3|) .is of general rectangular form, and extending longitudinally within the casing II the supporting member is fulcrumed intermediate its endson a shaft 32, one end of which is rigidly secured in and to the'casing re'ar wallV 2l. As shown, on one side of the fulcrum 32 or beneath the beuews 21, the supporting member u is provided'with a hollow rectangular end portion 33 integral with which the supporting member includes spaced?, longitudinally extending. substantially parallel side members 34 having aligning apertures adjacent the inner end of the rectangular end portion 33 to receive the shaft 32. Adjacent the shaft 32, the supporting member end portion 33 is provided with integrated top and side walls to which is removably connected a bottom wall or plate 31 for providing a recess 35 therebetween having an opening 33 facing toward the opposite end of the supporting member 30. Extending vinto the recess 35, an end portion of the leaf spring 3| rests against the upper surface of the bottom wall or plate 36, and adjacent its-end is clamped between the plate 36 and the member 33 b'ya screw 40. As shownin Figure 4, the width of the leaf spring 3| tapers down gradually from a maximum width, as at 52, intermediate its ends to an eyelet 4I which receives the screw 40. A bore 42 extending longitudinally through the supporting member portion 33 receives the shank 43 of a rotatable screw which has a threaded end portion 44 within the recess 35, and screwthreaded onto the screw there is an adjustment member 45 in the worm of a square nut for varying the effective length of the leaf spring 3|. One side of the nut 45 slidably engages the lower surfacel of the top wall of the recess 35 while an opposite side of the nut slidably engages the upper surface of the leaf spring 3|, these sides of the nut 45 preferably being rounded, as shown, to reduce friction between the parts. By rotating the screw, it will be seen that the nut 45 will move along the screw and that by moving the nut, for example, to the right, Figures l and 6, the effective'length of the spring 3| is shortened with corresponding increase in resistance of the spring to iiex.

The ends of the side members 34 are integrally joined together by a horizontal transverse wall 46, beneath which a rocker member 61 is carried by the free end of the leaf spring 3|.v From the maximum width, as at 52, of the leaf spring 3|, the spring tapers down toa minimum width, as at 52a, adjacent the free end of the spring. As shown in Figures 1 and 6, the rocker member 41 is provided With a lower flat surface which seats on the upper surface of the leaf spring 3| and terminates substantially at the. minimum Width of the spring 3| and also the rocker member is provided with an upwardly facing convex rocker surface 48 having a center of the radius of curvature which is preferably substantially at the point designated 48m-the convex surface 48 engaging the lower surface of the transverse wall 46 to rock thereon. Also carried by the free end of the leaf spring 3l but on the underside thereof is a second rocker member 50 which is adapted to flex the spring 3| longitudinally thereof, and, in so doing, to increase the tension or resistance of the spring to flex by coming in contact with a wider part of the spring. This second rocker member 50 is of general rectangular shape, and adjacent one end is secured to and adjacent the free end of the spring 3| by a screw 5I, which screw-threads onto the upper rocker member 41 and through an eyelet 53 on the free end of the spring, thus securing both rocker members to the spring 3|. Where the rocker member 50 is attached by the screw 5| to the spring 3|, an upper portion of the rocker member is provided with a nat surface as shown, which flat surface at substantially the point 48a or at the minimum width 52a of the spring, runs into a convex or rocker surface 54, preferably a segment of a cylinder for engaging the underside of the spring 3 I.

The other end of the rocker member 50 is disposed intermediate the ends of the spring 3| and is provided in its lower surface with a semicylindrical, transversely-extending recess in which a lower cross member ofa rectangular link 55 is retained by a removable plate 56 which is secured to the rocker member 50 by screws 51. Similarly, the upper cross member of the link '55 is retained in a recess of the drum segment 23 by a removable retainer plate 60 which is secured to the drum segment by screws 6 I.

Within the casing I5 immediately above the transverse wall v46 of the supporting member 30 there is a block-like support 62 which is rigidly secured to the casing end wall 20 for supporting an adjustable member in the form of a thumb screw 63. The adjustment screw 63 screwthreads vertically through the block 62 and has its lower end engaging the upper surface of the transverse wall 46. It will be seen that by means of the adjustment screw 63 the supporting member 30 may be moved about its fulcrum or shaft 32 to adjust the tension of the spring 3|. In order to ensure against upsetting of the adjustment of the supporting member 30. a helical coil spring 64 may be provided, and surrounding the screw is held under compression between the supporting block 62 and the head of the screw.

Referring now more particularly to Figures 2 and' 3, on the other side of the carburetor conduit I6 from the above described speed governor, the throttle valve shaft I3 projects externally of the conduit I0 and is journaled in a bearing 65 mounted in an external hollow boss 66 of the conduit I0. Rotatably mounted on the boss 66 is a tubular hub 61 of an operating lever 68, which hub is retained on the boss 66 by a retainer plate 69 engaging in an annular recess in the hub and rigidly secured to the conduit I0 by screws 1D. Within the hollow boss 66, the valve shaft I3 is provided with a reduced end portion 10a on which a sleeve 1I is provided having a laterally extending lug 12, the sleeve 1I being secured to the shaft I3 t0 rotate therewith by means of a nut 13 screwthreaded onto the outer end of the reduced shaft portion 10a.. Closing the outer end of the hub 61, a plate 14 is provided and secured to the hub by screws 15, the plate 14 having a lug 16 extending into the boss 66 for engaging the lug 12 on the valve shaft I3. The operating lever 68 is to be connected to the engine accelerator pedal having the usual return spring, not shown, for returning the lever 6B to the engine idling position shown in Figure 6.

Operation When an internal combustion engine controlled by the herein described governor is idling, the throttle control lever 68 will be held by a throttle return spring usually connected to the accelerator pedal in the position shown in Figure 6, and lug 16 engaging the lug 12 will hold the throttle valve I2 in engine idling position, Because of the relatively loW sub-atmospheric pressure in the intake manifold of an internal combustion engine during idling of the engine, the bellows 21 will be collapsed and through the strap 24 'will act to rotate the drum segment 23 in a counterclockwise direction facing Figures 1 or 6 and thus will aid in holding the throttle valve I2 in a near closed position against the opposition of the spring 3|. As the throttle valve is moved toward closed position, the drum segment 23, through the connecting link 55, pulls the lower anaemia on the under-surface of the wall 4l. It will be seen that as the member lll rocks it moves from 'its point of'contact at the narrowest point of 'the spring tpwarld the widest point thus meeting increased 'resistance of the spring. The rocking action of .the rocking member 41 causes the free end of the spring ll tobe bent downwardly while at the same time the-lowerv rocker member l0 rocks against the underside of the spring `Il longitudinally thereof. Asmore of the rocker surface 54 comes in contact with the lower surface of the spring 3 I it, will be seen thatthe resistance or tension of the spring is increased, causing the spring to take substantially the form shown in Figure 6. The spring Il acts to open the throttle valve I2, and the position to which the valve will be opened and consequently the high limit speed at which the engine will be permitted to operate may be regulated by the adjustment screw 6l. For example, it will be seen that when the adjustment screw 63 is rotated to move downwardly2 the spring 3| will beilexed and, since the end of the rocker member 50 which is connected to the link 55 will not move with movement of the support 30,*the result is that the spring 3| will be placed under additional tension and consequently will be adapted to correspondingly move the valve I2 further toward open position. When theaccelerator-operatedy lever 88 is moved clockwise facing Figures 1 or 6, the lug 12 carried by the valve shaft Il follows the lug 18 under action of the spring 3|. As the spring 3| tends to retum to the position shown in Figure 1 or to straighten out, rocker member I1 rocks on the under surface of the wall I8, permitting the jfree end of the spring to move upwardly, while at the same time the contact surface 54 of the lower rocker member 50 moves away from the underside of the spring 3|. This movement of the rocker member 50 in effect elongates the effective length of the spring Il, and in so doing moves from the widest part of the spring toward the narrowest part with corresponding decrease in resistance of the spring, with the result that the spring tension decreases and is overcome by the enginecreated suction acting on the'bellows 21. This results in a balanced condition between the bela lows 21 and the force of spring 3| which limits the open position of the valve to the desired position, determined, as previously mentioned, by means of the adjustment screw 63. The rate at which the force of the spring 3| changes as the rocker members 41 and 50 rock is 4determined partly by the tapers of the spring and partly by changing of the effective length of the spring.

While I have shown and described my invention in detail it is to be understood that the same is to be limited only by the appended claims for the vapex `of said tapered spring portion, the other ofsaid members extending from its respective spring side and also being formed with a rocking surface. and means providing a surface upon which said second-mentioned rocking surface isrockable. i

2. A device for resisting movement of an element comprising an elongated spring anchored at one oi' its ends and having a portion adjacent its opposite end tapered toward said last-mentioned end, means selectively movable between said spring ends for varying the effective spring length, a pair of rocker members secured to opposite sides ofsaid spring at said second-mentioned spring end, one `of said members extending from its respective spring side into operative connection with said element and being formed with a rocking surface tangent. to said respective spring side at approximately the apex of said tapered spring portion,` the other of said members extending from its respective spring side and also being formed with a rocking surface, and means providing a surface upon which said second-mentioned rocking surface is rockable.

3. A device for resisting movement of an element comprising an elongated springv anchored at one of its ends against flexing thereat and having a portion adjacent its opposite end tapered toward said last-mentioned end, a pair of rockermembers secured to opposite sides of said spring at said second-mentioned spring end, one of said members extending from its respective spring side into operative connection with said element and being formed with a rocking surface tangent to said respective spring side at approximately the apex of said tapered spring portion, the other of said members extending from its respective spring side and also being formed with a rocking surface, means providing a surface upon which said second-mentioned rocking surface is rockable, and means selectively operable for varying the position of said next to the last mentioned surface. i

4. A device for resisting movement of an element comprising an elongated springanchored at one of its ends and having a portion adjacent its opposite end tapered toward said last-mentioned end, means selectively movable between said spring ends for varying the effective spring length, a pair of rocker members secured to opposite sides of said spring at said second-mentioned spring end, one of said members extending from itsv respective spring side into operative connection with said element and being many changes may be made without departing a from the spirit and scope of the invention.

What I claim is: 1. A device for resisting movement of an element comprising an elongated spring anchored at one of its ends against flexing thereat and having a portion adjacent its opposite end tapered toward said last mentioned end, a pair of rocker V members secured to opposite sides of said spring at said second mentioned spring end, one of said members extending from its respective spring side into operative connection with said element and being formed with a rocking surface tangent to saidv respective spring side at approximately formed with a rocking surface tangent to said respective spring side at approximately the apex of said tapered spring portion, the other of said members extending from its respective .spring side and also being formed with a rocking surface, means providing' a surface upon which said second-mentioned rocking surface is rockable, and means selectively operable for varying the position of said next to the last mentioned surace.

5. A devicefor resisting movement of an element comprising an elongated spring anchored at one of its ends against flexing thereat and having a portion adjacent its opposite end tapered toward said last-mentioned end, a pair of rocker members secured to opposite sides of said spring at said second mentioned spring end and extending laterally therefrom, the outer end of one of said members being in operative connection with said element and' formed with a rocking surface tangent to said respective spring side at approximately the apex of Asaid tapered spring portion, the outer end of the other of said members also being formed with a rocking surface, and means providing a surface upon which said second-mentioned rocking surface is rockable.

6. A device for resisting movement of an element comprising an elongated spring anchored at one of its ends against flexing thereat and having a portion adjacent its opposite end tapered toward said last mentioned end, a pair of rocker members secured to opposite sides of said spring at said second-mentioned spring end, one of said members extending from its respective spring side into operative connection with s aid element and being formed with a rocking surface the center of curvature of which establishes tangency between said surface and said last-mentioned spring side at approximately the apex of said tapered spring portion during spring inactivity, the other of said members extending from its respective spring side and being formed with a rocking surface the center of curvature of which resides approximately at said apex, and means providing a surface upon which said second-mentioned rocking surface is rockable.

'7. A device for resisting movement of an element comprising an elongated, normally at spring anchored at one of its ends against ilexing thereat and having a portion adjacent its opposite end tapered toward said last-mentioned end, a pair of rocker members each having a iat surface secured to one of the two opposite sides of said spring and extending from said secondmentioned spring end to the apex of said tapered spring portion, one of said members extending laterally outwardly from its respective spring side into operative connection with said element and being formed with a rocking surface tangent to the inner end of its respective flat surface and curved away from said respective spring side and in the general direction of said first-mentioned spring end, the other of said members extending laterally outwardly between the ends of its respective fiat surface and being formed at its outer end with a rocking surface, and means providing a surface upon which said second-mentioned rocking surface is rockable.

8. A device for resisting movement of an element comprising an elongated, normally at spring anchored at one of its ends against exing thereat and having a portion adjacent its opposite end tapered toward said last-mentioned end, a pair of rocker members each having a fiat surface secured to one of the two opposite sides of said spring and extending from said second-mentioned spring end to the apex of said tapered spring portion, one of said members extending laterally outwardly, from its respective spring side into operative connection with said element and being formed with a rocking surface tangent to the inner end of its respective at surface and curved away from said respective spring side and in the general direction of said first-mentioned spring end, the other of said members extending laterally outwardly between the ends of its respective nat surface and being formed at its outer end with a rocking surface, and means providing a surface upon which said second-mentioned rocking surface is rockable, said first-mentioned rocking surface having` a center of curvature laterally spaced from saidv first mentioned spring side and said second mentioned rocking surface having a center of curvature residing substantially at said apex.

9. A device for resisting movement of an element comprising 'an elongated, normally flat spring anchored at oneof its ends and hav- .ing a portion adjacent its opposite end tapered toward said last-mentioned end, means operable for selectively varying the effective length 'of said spring, a pair of rocker members each having a flat surface secured to one of the two opposite sides of said spring and extending from said second-mentioned spring end to the apex of said tapered spring portion, one of said members extending laterally outwardly from its respective spring side into operative connection with said element and being formed with a rocking surface tangent to the inner end of its respective flat surface and curved away from said respective spring side and in the general direction of said first-mentioned spring end, the other of said members extending laterally outwardly between the ends of its respective fiat surface and being formed at its outer end with a rocking surface, means Aproviding a surface upon which said second-mentioned rocking surface is rockable, and means operable for selectively varying the position of the next to the last mentioned surface.

10. A device for resisting movement of an element comprising an elongated, normally ilat spring tapered in opposite directions along its .length so as to have a portion intermediate its two ends of greatest width and a portion adjacent each of said ends of least width, said spring being anchored at one of said ends against flexing thereat, a pair of rocker members each having a flat surface secured to one of the two opposite sides of said spring and extending from the other of saidspring ends to said position of lea-st width thereadjacentr one of said members extending laterally outwardly from its respective spring side into operative connection with said element and being formed with a rocking surface tangent to the inner end of its respective fiat surface and curved away from said respective spring side and in the general direction of said one spring end, the other of said members extending laterally outwardly between the ends of its respective at surface and being formed at its outer end with a rocking surface, and means providing a surface upon which said second-mentioned rocking surface is rockable.

AUGUST W. KRETZSCHMAR. 

